f:   J£>y 


Circular  No.  107. 


United  States  Departing!)  <>i  A 

BUREAU  OK  ENTOMOLOG 

L.  O.  HOWAKI).   I 


WHAT  CAN  BE  DONE  IN  DESTROY! 
WEEYIL  DURING  THE 

By  W.  I>.  Huntbr, 
In  Charge  of  Southern  "Field  Crop  I 

IMPORTANCE    OF    WINTl'.K    WORK. 

boll  weevil  attar  test  attention  daring  tin-  growing  season 

of  cotton,  for  tin*  simple  reason  that  its  damage  ia  then  moat  evident. 
When  the  infest  d  Bquan  -  ling  by  millions  everyday  the  planter 

is  driven  to  most  Btrenuoufl  efforts  to  check  the  loss.     The  summer 
er,  is  the  one  in  which  it  is  most  difficult  to  combat  the 
il.     The  ]  !  he  attaeked  in  various  ways  at  different  seasons 

of  the  year.  This  circular  attempts  to  point  out  what  can  be  done  in 
the  winter  when  the  weevils  are  in  hibernating  quarters  and  when  nat- 
ural conditions  are  assisting  the  tanner  greatly  by  reducing  the  number 
that  will  he  able  to  survive  until  spring.  At  this  time  the  farmer  can 
Undoubtedly  accomplish  more  than  by  hand-picking  weevils  and  squares 
or  any  other  direct  method  of  control  that  can  be  put  into  operation  in 
the  summer  Beason.  advantage  that  winter  work  has  in  many 

is  that  it  involves  no  special  outlay  and  consequently  adds  nothing 
to   th  "f  producing   cotton.      The  work  can  be  done    during   the 

quiet  period   of  the  winter  and   at  such  times  as  will   not  interfere  with 

•neral  work  of  the  plantation.  Even  on  plantations  run  largely  or 
entirely  by  "wages  hands"  this  work  woull  undoubtedly  warrant  an 
outlay  on  the  part  of  the  planter.  As  a  matter  of  fact  the  winter  season 
COUld  well  he  made  the  most  active  of  the  year  as  far  as  the  destruction 
of  the  weevil  is  concerned. 

It  is  true  that  the  Texas  farmers  have  not  paid  much  attention  to 
work  against  the  weevil  in  the  winter,  hut  this  does  not  by  any  means 
indicate  that  such  work  will  not  he  of  prime  importance  to  the  planters 

ppi.     Nature  has  afforded  the  Texas  tinner 
many  advant  inter  in  1  rn  part  of  the  cotton  belt. 

As  ha-  been  pointed  out  in  other  publications  of  the  Bureau  of  Ento- 
mology, the    '  ppi  Valley  planter  will  he  compelled  to  contend 

-t  many  more  weevils  each  spring  than  the  climatic  conditions  in 
•er  permitted  to  survive.      For  instance,  in  the  spring  of 
etermined   by  Mr.  Wilmon   Newell,  secretary  of  the  5 
crop  pest  commission  of  Louisiana,  that  as  many  as  6,0<X)  hihernated 
weevi  re  made  their  appearance  in  certain  cotton  fields  in  Avoy- 

elles Parish,  Louisiana.     This  a  survival  of  weevils  far  heyond 

what  has  ever  been  found  in  Texas.  There  are  many  other  indications 
of  the  special  seriousness  of  the  weevil  problem  in  the  .Mi-sir?ippi  Val- 

A« 31 


ley.  All  this  demonstrates  that  the  planters  in  regions  recently  invaded 
by  the  weevil  must  resort  to  every  means  of  control  that  is  known  and 
must  utilize  to  the  fullest  extent  such  methods  as  the  Texas  farmers 
may  not  have  been  compelled  to  practice. 

The  all-important- step  in  the  control  of  the  weevil  is  the  destruction 
of  millions  of  individuals  and  the  prevention  of  the  development  of 
many  more  by  uprooting  and  burning  the  cotton  plants  in  the  fall. 
This  is  a  step  that  indications  show  clearly  is  going  to  be  indispensable 
in  the  Mississippi  Valley.  In  the  light  of  what  is  now  known  it  would 
be  folly  for  planters  to  attempt  to  produce  cotton  unless  they  follow 
this  practice  religiously.  If,  for  any  reason,  the  cotton  plants  have  not 
been  removed  in  the  fall,  some  good  can  be  accomplished  by  their 
removal  later  in  the  season.  The  proper  thing  to  be  done  by  the 
planter  who  desires  to  reduce  weevil  damage  to  the  minimum  is  to 
combine  the  fall  destruction  of  the  plants  with  such  measures,  to  be 
taken  later  in  the  season,  as  are  outlined  in  this  circular.  The  advice 
now  given  is  not  to  depend  upon  winter  work  altogether  for  the  control 
of  the  weevil.  The  winter  work  is  merely  a  second  step,  to  be  taken  in 
connection  with  the  destruction  of  the  weevils  and  the  prevention  of  the 
maturity  of  the  fall  broods  by  uprooting  and  burning  the  plants.  Where 
that  step  has  not  been  taken,  the  work  outlined  in  this  circular  is  the 
main  dependence  of  the  planters  at  this  time. 

WHERE    WEEVILS   ARE    TO    BE    FOUND   DURING   THE    WrINTER. 

The  whole  question  of  what  can  be  done  to  destroy  the  weevils  in 
the  winter  depends  upon  where  they  are  to  be  found.  The  Bureau  of 
Entomology  has  taken  pains  to  determine  the  localities  in  which  the 
weevils  secrete  themselves  during  the  winter  months.  Some  weevils 
fly  outside  of  the  cotton  fields  into  the  timber  before  frost  has  killed  the 
cotton.  Of  course,  such  individuals  as  fly  great  distances  from  the 
cotton  fields,  or  into  heavy  timber,  are  entirely  beyond  the  reach  of  the 
planter.  The  remainder  of  the  weevils,  how7ever — those  remaining  in 
and  about  the  cotton  fields — are  more  or  less  at  the  mercy  of  the 
planter  for  several  months  during  the  winter. 

In  cotton  fields  and  in  their  immediate  vicinity  weevils  have  been 
found  hibernating  in  four  principal  situations:  First,  in  burrs  and  un- 
opened bolls  on  the  plants ;  second,  in  bolls  or  portions  of  bolls  that 
have  been  knocked  to  the  ground;  third,  under  such  trash  as  leaves 
and  grass  abounding  in  most  cotton  fields;  fourth,  in  the  cracks  in  the 
ground  caused  by  drying. 

The  numbers  of  weevils  found  in  the  situations  just  mentioned  show 
clearly  what  opportunities  the  farmer  has  for  their  destruction.  On 
January  16,  1907,  a  field  near  Wolfe  City,  Tex.,  showed  from  363  to 
1,500  live  weevils  per  kcre  in  the  burrs  still  hanging  to  the  plants. 
These  were  generally  in  the  partly  opened  locks  where  weevils  had 
matured  in  the  fall,  but  some  were  in  locks  from  which  all  of  the  cotton 
had  been  removed.  On  January  27,  1907,  as  many  as  2,250  weevils 
per  acre  were  found  on  the  ground  in  a  cotton  field  near  Dallas,  Tex. 
The  number  was  determined  by  raking  all  of  the  trash  carefully  from  a 
square  rod  of  ground  and  examining  it  in  the  laboratory.  On  Decem- 
ber 18  living  weevils  at  the  rate  of  1,056  per  acre  were  found  at  Dallas. 
On  January  16  320  living  weevils  per  acre  were  found  in  burrs  and 
under  leaves  and  grass  in  a  cotton  field  at  Victoria,  Tex.     On  Novem- 

A6 31 


her  1  ">  1  weevils  were  found  in  the  ciacks  around  the  bftMfl  of  22 
cotton  plants  growing  near  Dallas.     This  indicates  a  total  Dumber  of 

uc.vils  per  a,  re  in  such  situations  in  this  field  of  1,090. 

Practically  all  of  the  weevils  to  be  found  in  the  situations  described 
can  be  killed  by  raking  and  burning  the  trash,  excepl  those  in  cracks 
in  the  ground,  and  these,  in  the  majority  of  cases,  would  probably  be 
crushed  by  winter  plowing  of  the  fields. 

PLOWING    NOT    EFFECTIVE. 

The  point  may  he  raised  thai  winter  plowing,  by  burying  the  weevils 
found  iii  trash  on  the  surface,  migbl   have  the  same  .  burning. 

On  the  contrary,  experiments  have  shown  that  weevils  can  easily  make 
their  way  through  several  inches  of  soil.  Consequently  such  work  in 
genera]  is  as  likely  to  protect  as  to  destroy  the  weevils,  of  course,  it 
heavy  rams  should  follow  immediately  after  plowing,  it  is  possible  that 
some  soils  would  he  so  compacted  as  to  prevent  the  emergence  of 
weevils.  Nevertheless,  this  could  not  happen  under  usual  conditions. 
In  the  case  of  weevils  in  cracks,  destruction  would  not  result  from 
burial  hut  from  crushing. 

What  lias  jusl  been  stated  should  not    he  taken   to  mean  that  winter 
plowing  should  not  be  followed.      As  a  matter  of  fact,  the  winter  work- 
ing of  the  fields  should  he  practiced,  not  only  on  general  principles,  hut 
--ist  in  procuring  an  early  crop.      The  present  purpose  is  merely  to 
point  out  how  to  destroy  the  boll  weevil  in  the  winter.     Regardl< 

ther  benefits,  winter  plowing  can  not  he  depended  upon  to  actually 
kill  many  weevils. 

WEEVILS  THA'f  CAN    BE    BEACHED   OUTSIDE   or  COTTON    FTELD8. 

In  addition  to  those  in  the  cotton  fields  themselves,  many  weevil- 
can  he  reached  that  have  found  winter  quarters  along  turn-row-,  in 
ditches,  along  fences,  and  in  the  trash  that  is  frequently  allowed  to 
accumulate  around  seed  houses.  Fire  is  again  the  agent  of  destri; 
at  the  com m anil  of  the  fanner.  Careful  burning  of  turn-rows  and  ditches 
and  cleaning  of  fence  corners  and  similar  situations  w  ill  result  in  the 
death  of  many  weevils  that  might  survive  to  damage  the  crop  of  the 
following  season. 

The  work  of  burning  and  cleaning  the  plantation  should  not  stop 
with  the  immediate  vicinity  of  cotton  fields.  Many  weevils  By  into 
corn  fields,  where  they  find  suitahle  quarters  for  passing  the  winter. 
These  fields,  on  a  cotton  plantation,  should  he  cleaned  during  the  win- 
ter as  thoroughly  as  the  fields  where  cotton  has  been  growing  or  is  to  be 
grown  during  the  ncv  -  -  .  It  has  been  found  that  sorghum  fields 
furnish  exceptionally  favorable  opportunities  for  hibernating  weevils. 
The  heavy  Btubble  left  by  this  crop  catches  grass  and  general  debris 
blown  about  by  the  wind,  which  then  becomes  heavily  matted.  Here 
many  weevils  are  to  he  found  during  the  winter.  In  many  cases  in 
-  the  earliest  appearing  weevils  and  the  greatest  damage  to  the 
crop  have  been  shown  to  he  chargeable  to  neighboring  Borghum  fields 
which  have  served  as  winter  quarters  for  the  pest. 

Many  weevils  undoubtedly  find  hibernating  quarters  in  trash  a 
railroad  rights  of  way  as  well  as  along  wagon  mads.     The  importance 
of  such  means  furnished  the  weevil  for  passing  the  winter  1  great 

where,  as  in  many  cases,  the  roads  or  railroads  pass  through  localities 


UNIVERSITY  OF  FLORIDA 

II I  Mill  II II II' 

3  1262  09216  5132 

where  cotton  fields  adjoin  the  public  property.  It  should  be  the  duty 
of  railroad  and  county  authorities  in  such  cases  to  assist  the  farmers  as 
far  as  practicable  by  removing  the  shelter  for  the  weevil. 

WEEVILS   IN   COTTON   SEED. 

Cotton  seed  has  frequently  been  supposed  to  furnish  exceptionallv 
favorable  winter  quarters  for  the  weevil.     It  has  been  shown  that  mam 
weevils  pass  through  the  gins  and  are  later  to  be  found  in  the  bulk  i 
ton  seed  in  storage.     Up  to  a  certain  time  in  the  winter  cotton  seed  i« 
very  likely  to  contain  live  weevils.     Many  experiments,  however  have 
shown  that  very  few  are  able  to  survive  in  this  medium  until  spring 
This  seems  to  be  due  principally  to  the  absence  of  moisture.     Repeat- 
edly numbers  of  weevils  have  been  placed  in  cotton  seed  in  the  fall 
Altogether  6,600  weevils  have  been  used  in  these  experiments.     They 
were  placed  under  a  variety  of  conditions.     Although  many  have  sur- 
vived until  the  middle  of  winter,  only  two  lived  until  the  first  of  April 
It  is  therefore  clear  that  cotton  seed  itself  is  not  an  especially  dangerous 
commodity.     Although  it  is  true  that  the  earliest  weevils  frequently 
make  their  appearance  in  the  vicinity  of  seed  houses,  this  is  to  be 
accounted  for  by  the  fact  that  the  insects  find  quarters  under  the  build- 
ing and  under  the  trash  that  is  allowed  to  accumulate  in  such  situations 
rather  than  in  the  cotton  seed  itself. 

CONCLUSION. 

The  climatic  and  labor  conditions  surrounding  cotton  production  in 
Louisiana  and  Mississippi  leave  no  doubt  that  the  planters  in  those 
States  must  not  overlook  any  important  means  of  controlling  the  boll 
weevil.  This  circular  points  out  one  important  and  inexpensive  means 
that  can  be  practiced  by  every  planter.  It  is  of  special  importance  in 
the  humid  regions  recently  invaded  where  fears  of  disaster  are  now 
commonly  entertained.  The  Department  of  Agriculture  urges  that 
cotton  raisers  take  advantage  of  the  enemy  while  they  have  the  oppor- 
tunity and  by  the  means  herein  described  greatly  increase  the  chances 
for  producing  a  crop  the  coming  season. 

Approved: 

James  Wilson, 

Secretary  of  Agriculturi . 

Washington,  D.  ('..  December  t9,  1908. 

A6 31 

o 


